57.—Second Pulley System.details

The only system of pulleys frequently employed for hoisting is what is called the second system, where there are two blocks of pulleys, one attached to the weight, and the other to the beam; and where the same rope passes round all (fig. 57). The mechanical advantage in this case is simply equal to the number of strings sup­porting the weight: which in the figure happens to be four. (p. 138)